Study On The Micromechanical Behavior Of Asphalt Pavement Under The Vehicle-road-bridge Interaction

With the rapid development of highway construction in our country,the number of bridges is increasing.The bridge deck is excited by the vehicle load,but also acco MPanied by the vibration of the bridge,which causes the early damage of the bridge deck before it was not to reache the designed service life,which brings great pressure to the later maintenance.The failure of bridge deck is the macroscopic mechanical behavior after the interaction of the micro structure inside the asphalt material.The cause of the damage is the micro structure and mechanical relationship of the material.Therefore,it is necessary to further study the micro mechanical behavior of the bridge deck under the vehicle bridge interaction from the micro perspective.At present,most of the research on the numerical calculation of the mechanical response and failure of the bridge deck under the action of the actual vehicle load is on the macro,while the research on the micro is mostly on the small-scale model of the asphalt specimen due to the time required for calculation,both of which are difficult to reflect the micro mechanical behavior and damage for the bridge deck under the action of the actual vehicle bridge interaction.In this paper,asphalt mixture as the main research object,through the simulation experiment to calibrate the micromechanical parameters of the asphalt material,using the discrete element to build the micromechanical model of the simple supported bridge.The bridge model includes the asphalt upper layer,the lower layer,the concrete layer and the steel plate,and the correctness of the bridge micromechanical model is verified by finite element calculation results.The dynamic tire force under the vehicle bridge interaction is used as the load of the bridge micromechanical model,the mechanical response of the bridge decks is calculated,the mechanical characteristics of the bridge deck pavement are analyzed from the micromechanical,and the influence of different vehicle speed and different vehicle load on the mechanical response of the bridge and bridge deck is explored.By building a simplified pavement model similar to the bridge model,the dynamic response of the bridge deck and asphalt pavement under the same coupling dynamic load is studied.The actual vehicle load is simplified as static load,i MPact load and sinusoidal load.The damage behavior and failure mechanism of asphalt deck and highway asphalt surface under different load forms are studied.In order to study the bending and tensile damage mechanism of bridge deck materials,constant strain rate loading and dynamic load failure experiments of asphalt mixture specimens were carried out,and the meso mechanical model of asphalt mixture was constructed for simulation calculation to study the local stress change and damage generation and development trend.